2002 Prius C1259, C1241, C1213, C1214, help!

Hi forum world, I'm new to all this but I'd love some advice about my 2002 Prius.

I replaced her main battery 7/15/2020 with a refurbished one after dealing with dash warnings for a few months. I had initially thought the Aux. battery was the issue, so got into the habit of pulling over and resetting it but also eventually replaced it. When that didn't do the trick, I took it in for the big swap. She drove fine for several hundred miles, but then the warnings came back and I started losing power in the pedal on the highway (which was super fun!). Then all of a sudden, no power above 35mph, then there's not even power in reverse!

Took her back to the shop, but a new one because I'd moved to Baltimore in the meantime. After diagnostics, they came back with error codes C1241, C1259, C1213, C1214 and C1215.

They quoted me $3600 for a battery replacement, even though they outsource the job to another company. I promptly said no thank you, took my car back and am looking for an alternate solution. After reading a lot on the forums and doing other research, I have an idea of what might be happening but I'd love y'alls opinion before I go to yet another mechanic... Or spiral down a youtube rabbit hole in the wrong direction!

Thanks in advance!
-B&Cosette

 

Thanks y'all, I definitely have had to disconnect the 12v for 2min or more before. It used to work temporarily, but doesn't stop the alarms from ringing as soon as the car is in READY now. I'm going to pull it and clean the terminals and ground, then try again. Will update with results!

 

Sorry, had a busy weekend! I pulled the 12v battery and the terminals are spotless, so my next step is to take it in to get volt-tested. I'm also reaching out to Prius repair in Annapolis by phone today, will let you know what they say!

 

Hi folks,
Sorry for the delay in updating! So the Aux battery was not grounded, that has since been fixed and volts read fine. The error codes however have gotten more extreme, I am now reading a P3006 and C1521 in addition to the others. My theory is the HV battery ECU or the Brake ECU in corrupted smehow. Any thoughts?

-B

 

Thanks Josey, it's not at the Annapolis shop unfortunately and that's part of the problem... This mechanic (mech #3) doesn't know half as much about hybrids as y'all on this site. I had recently replaced the HV battery so my suspicion is still the HV ECU, it might have been a botched install on the replacement battery. I also read that the sheathing on the wires connecting battery to ECU are notorious for corroding as well, anyone else have experience with this + P3006 code?
And the first thing I'm going to do Monday is ask them for all current codes, when they were read (before or after the 12v was grounded), then to unground the 12v for a few minutes, plug it back in and see if the codes are cleared.